Kimber 8TC beater?

"It's an old system that was in hibernation for years til a few months ago. Presently, system sounds quite constricted...quite thin and "smallish" sounding. Amps retubed recently."

If the equipment has been siting for years, it will probably need to be broken in again. Make sure it has been playing for at least 100 hours.

Given your description above, I'm not sure a new pair of cables will be able to take care of all that. Best Buy sell AQ. Maybe buy a pair from them and if they don't fix the problem, you can always bring them back.

"I think I could squeeze out a bit more "fullness" by repostioning my speakers a little but that leaves the smallish image size problem."

If you are looking to increase image size, you can control that somewhat with cable choice. Its better to do that type of thing with components, but for small amounts, you may be able to do it with cables. Generally speaking, the cable design that seems to yield the biggest, roust type of image, is a well designed stranded cable. The 8tc is a good choice for that. Cardas is a little better even. I have some Golden Reference that gives a nice, big image. It may seem like an odd choice, but a pair of MIT avt1 or 2 will image like that, as well. But whatever you go with, don't expect miracles. There's only so much a cable can do. That said, I do think your Supra Ply's may be working against you a bit. It wouldn't be a bad idea to try something different.